摘要
Novel visible-light-sensitive ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> heterojunction photocatalysts are successfully fabricated by a facile solvothermal method for the enhanced photocatalytic degradation of bisphenol A (BPA) under different light sources. The photocatalytic degradation efficiency and rate of BPA by ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> under the irradiation of different light sources follow the order 465 nm visible light > solar simulator > 365 nm UV light. The reaction rate of BPA by ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> in the presence of 465 nm visible light is 42 times higher than that under 365 nm UV light irradiation. In addition, the ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> nanocomposites exhibit excellent recycling and reusability and can retain their stable photocatalytic activity toward BPA photodegradation for at least 10 cycles of reaction with rate constants of 0.191-0.218 min <sup>-1</sup> under visible light irradiation. The photogenerated holes as well as oxygen-containing radicals are identified to be the predominant reactive species responsible for the photodegradation of BPA in the ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> system. The possible reaction mechanisms for BPA photodegradation by p-n heterojunction ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> are also proposed. Results obtained in this study clearly demonstrate the superior visible-light-driven photoactivity of ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> toward BPA photodegradation and can open an avenue to fabrication of p-n heterojunctions of photocatalysts with a wide variety of potential applications in the fields of photocatalysis, water splitting and energy conversion.